Binding of [125I]-labeled Bolton-Hunter substance P ([125I]-BHSP) to NK1 receptors was investigated in the spinal cord of young (3-4 month) and aged (14-16 month) rats. In homogenates of whole spinal cord, the affinity (equilibrium dissocation constant, ~ 210 pM) and maximum density of [125I]-BNSP binding sites (~ 0.25 fmol/mg wet weight) were similar for young and aged rates. Autoradiographic studies revealed a similar distribution of [125I]-BHSP sites in both young and old rats at all spinal levels. Intense binding was observed in the superficial dorsal horn (laminae I-III), grey commissure (lamina X) and thoracic intermediolateral cell column (IML) with lower levels of binding in the deeper dorsal horn (laminae IV-VI) and ventral horn (laminae VII-IX). However, the density of [125I]-BHSP sites was significantly (P < 0.05) lower in lamina X of lumbar sections of aged rats compared with young controls. These studies suggest that ageing is associated with a selective loss of NK1 receptors in lamina X of the lumbar spinal cord, although the affinity of NK1 receptors in aged rats is unchanged.

Item Type:	Refereed Article
Research Division:	Biomedical and Clinical Sciences
Research Group:	Pharmacology and pharmaceutical sciences
Research Field:	Basic pharmacology
Objective Division:	Health
Objective Group:	Other health
Objective Field:	Other health not elsewhere classified
UTAS Author:	Maguire, CM (Mrs Christine Maguire)
UTAS Author:	Geraghty, DP (Professor Dominic Geraghty)
ID Code:	12924
Year Published:	1998
Web of Science® Times Cited:	4
Deposited By:	Health Sciences A
Deposited On:	1998-08-01
Last Modified:	2011-08-05
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